Introduction

Study on precipitation in order to determinate the compounds in the rain and their effects on quality of surface and ground water and also, soil resource is very important. In this research, sampling of precipitation was performed in Guilan Province in order to study rain composition for a period of 5 months (from March, 2013 up to June 2013). Sampling was performed from four meteorology synoptic stations located at four counties of Guilan Province consisting of Manjil, Lahijan, Rasht and Bandaranzali. In Rasht, two sampling stations have been determined consisting of Rasht Airport and Moallaem Blvd., synoptic stations. In this study, all precipitations in this time limit were sampled with consideration to the amount of precipitation in mentioned time. The samples were obtained at the beginning of precipitation that were 35 samples from all stations. For all samples, pH, EC (Electrical Conductivity), nitrate, nitrite, sulfate, ammonia, calcium, magnesium, sodium and potassium have been measured. Nitrate, nitrite and sulphate were determined through spectroscopic method based on standard methods. The results indicate that maximum amount of pH has been in Moallem Bld., of Rasht 7.92 and minimum amount of pH has jointly been at Rasht Airport and Lahijan stations, 6. Average amount of nitrate and nitrite at all precipitations are 0.14±0.19 and 0.06±0.02 mg L-1, respectively and minimum amount of nitrate in 14 samples has been less than detection limit of method. Average of other factors has been consisting of calcium 15.82±7.69, magnesium 7.50±5.06, sodium 2.50±0.50 and potassium 0.24±0.07 mg L-1. Amount of nitrogen and sulfur input studied up to March, 2013, has been calculated in the Province, 1.94 kg and 1.06× Kg. year-1, respectively. Comparison of the amount of nitrogen and sulfur input in a year and with other regions in the world